code: def _verify_email(email: str) -> _Activation:
      """Verify the user's email address.
  
      The email can either be an empty string (if the user chooses not to enter
      it), or a string with a single '@' somewhere in it.
  
      Parameters
      ----------
      email : str
  
      Returns
      -------
      _Activation
          An _Activation object. Its 'is_valid' property will be True only if
          the email was validated.
  
      """
      email = email.strip()
  
      # We deliberately use simple email validation here
      # since we do not use email address anywhere to send emails.
      if len(email) > 0 and email.count("@") != 1:
          LOGGER.error("That doesn't look like an email :(")
          return _Activation(None, False)
  
      return _Activation(email, True)
  
imports: import json
  import os
  import sys
  import textwrap
  from collections import namedtuple
  from datetime import datetime
  from typing import Optional
  from uuid import uuid4
  import click
  import toml
  from streamlit import env_util, file_util, util
  from streamlit.logger import get_logger
label_desc: Use image node_id 3 for calling a global function with example usage: _verify_email(email) and returns: _Activation, _Activation